This invention relates generally to supported catalysts, and more particularly to supported metallocene catalysts and methods for their production and use.
Metallocene catalyst systems and their use for olefin polymerization are well known. Metallocene catalysts are single-sited and differently activated compared to conventional Ziegler-Natta catalysts. A typical metallocene catalyst system includes a metallocene catalyst, a support, and an activator. Upon attaching or xe2x80x9cfixingxe2x80x9d the catalyst to the support, the catalyst is generally referred to as a supported catalyst. For many polymerization processes, supported catalysts are required, and various methods for attaching metallocene catalysts to a support are known in the art. Supports suitable for use with metallocene catalyst are generally porous materials and can include organic materials, inorganic materials and inorganic oxides.
However, many supports contain reactive functionalities. In some instances, these reactive functionalities may deactivate or reduce the activity of the catalyst fixed to the support. When this occurs, the addition of more catalyst to the catalyst system may be necessary to ensure sufficient polymer production during olefin polymerization. Increasing the catalyst concentration in the catalyst system to compensate for activity reduction caused by reactive functionalities is generally undesirable for many reasons. For instance, generally the addition of more catalyst may also require the addition of more activator. As such, increasing the concentrations of both catalyst and activator to overcome the effects of catalyst deactivation by reactive functionalities substantially increases the cost of olefin polymerization.
Hydroxyl groups are an example of a reactive functionality present on some supports which deactivate metallocene catalysts. Hydroxyl groups are present on supports, such as inorganic oxides. An example of an inorganic oxide is silica gel. As such, when using silica gel to support a metallocene catalyst, it is desirable to remove, reduce or render inactive a sufficient number of the hydroxyl groups. Methods of removing or reducing hydroxyl groups include thermal and/or chemical treatments. The removal of hydroxyl groups is known as dehydroxylation.
Thermally treating or heating the support material generally avoids contamination of the support by undesirable chemicals. However, in the case of many porous supports, such as silica gel, heating the support may fail to achieve sufficient dehydroxylation. Chemically treating the support material can be expensive and may result in contamination of the support.
Thus, there remains a need for increasing the activity of supported metallocene catalyst systems. Particularly, there remains a need for improved supported metallocene catalysts wherein the reactive functionalities of the support are reduced and/or deactivated.
The present invention provides a highly active metallocene supported catalyst composition. Generally, the inventor has discovered that when at least one metallocene catalyst is bound to a fluorided support, the activity of this metallocene supported catalyst composition is higher compared to the activity of the same metallocene catalyst bound to a non-fluorided support. These non-fluorided supports included supports to which no fluorine was added or a halide other than fluorine was added.
In one embodiment, the metallocene supported catalyst composition includes a metallocene catalyst and a support composition. The support composition may be represented by the formula: Sup F, wherein Sup is a support, and F is a fluorine atom bound to the support. The support composition may be a fluorided support composition.
In another embodiment, the metallocene supported catalyst composition includes a support composition represented by the formula: Sup L Fn. xe2x80x9cSupxe2x80x9d may further be defined as a support selected from the group which includes talc, clay, silica, alumina, magnesia, zirconia, iron oxides, boria, calcium oxide, zinc oxide, barium oxide, thoria, aluminum phosphate gel, polyvinylchloride and substituted polystyrene and mixtures thereof.
xe2x80x9cLxe2x80x9d is a first member selected from the group which includes (i) bonding, sufficient to bound the F to the Sup; (ii) B, Ta, Nb, Ge, Ga, Sn, Si, P, Ti, Mo, Re, or Zr bound to the Sup and to the F; and (iii) O bound to the Sup and bound to a second member selected from the group consisting of B, Ta, Nb, Ge, Ga, Sn, Si, P, Ti, Mo, Re, or Zr which is bound to the F;
xe2x80x9cFxe2x80x9d is a fluorine atom; and
xe2x80x9cnxe2x80x9d is a number from 1-7.
The support composition desirably may be a fluorided support composition. The metallocene supported catalyst composition may also include boron and may also include an activator, such as alkylalumoxane or MAO or haloaryl boron or aluminum compounds.
The metallocene catalyst may be represented by the formula: CpmMRnXq, wherein Cp is a cyclopentadienyl ring which may be substituted, or derivative thereof which may be substituted, M is a Group 4, 5, or 6 transition metal, R is a hydrocarbyl group or hydrocarboxy group having from one to 20 carbon atoms, X may be a halide, a hydride, an alkyl group, an alkenyl group or an arylalkyl group, and m=1-3, n=0-3, q=0-3, and the sum of m+n+q is equal to the oxidation state of the transition metal.
The present invention also provides a method of making the metallocene supported catalyst composition. The method step includes contacting the metallocene catalyst with a support composition, desirably a fluorided support composition, under suitable conditions and for a sufficient time, wherein the support composition is represented by the formula Sup L Fn. The support composition, and particularly the fluorided support composition, may be made by contacting a hydroxyl group containing support material with at least one inorganic fluoride under suitable conditions and for a sufficient time wherein the fluoride becomes bound to the support.
The present invention also provides an olefin polymerization method. The steps of the olefin polymerization method include contacting a polymerizable olefin with the metallocene supported catalyst composition under suitable conditions and for a sufficient time. Desirably, the polymerizable material is propylene. The polymerizable olefin may be formed into numerous articles, such as, for example, films, fibers, fabrics, and molded structures.
This invention is directed to metallocene catalyst compositions comprising the reaction product of at least three components: (1) one or more metallocenes; (2) one or more activators; and (3) one or more fluorided support compositions.
As used herein, the phrase xe2x80x9cfluorided support compositionxe2x80x9d means a support, desirably particulate and porous, which has been treated with at least one inorganic fluorine containing compound. For example, the fluorided support composition can be a silicon dioxide support wherein a portion of the silica hydroxyl groups has been replaced with fluorine or fluorine containing compounds.
As used herein, the term xe2x80x9csupport compositionxe2x80x9d means a support, desirably particulate and porous, which has been treated with at least one fluorine containing compound. Suitable fluorine containing compounds include, but are not limited to, inorganic fluorine containing compounds and/or organic fluorine containing compounds.
In the specification, including the examples certain abbreviations may be used to facilitate the description. These may include: Me=methyl, Et=ethyl, Bu=butyl, Ph=phenyl, Cp=cyclopentadienyl, Cp*=pentamethyl cyclopentadienyl, Ind=indenyl, Ti=titanium, Hf=hafnium, Zr=zirconium, O=oxygen, Si=silicon B=boron, Ta=tantalum, Nb=niobium, Ge=germanium, Mg=magnesium, Al=aluminum, Fe=iron, Th=thorium, Ga=gallium, P=phosphorus, Mo=molybdenum, Re=rhenium, and Sn=tin.
Supports
Supports suitable for use in this invention are generally porous materials and can include organic materials, inorganic materials and inorganic oxides. Desirably, supports suitable for use in this invention include talc, clay, silica, alumina, magnesia, zirconia, iron oxides, boria, calcium oxide, zinc oxide, barium oxide, thoria, aluminum phosphate gel, polyvinylchloride and substituted polystyrene and mixtures thereof.
Particulate silicon dioxide materials are well known and are commercially available from a number of commercial suppliers. Desirably the silicon dioxide used herein is porous and has a surface area in the range of from about 10 to about 700 m2/g, a total pore volume in the range of from about 0.1 to about 4.0 cc/g and an average particle diameter in the range of from about 10 to about 500 xcexcm. More desirably, the surface area is in the range of from about 50 to about 500 m2/g, the pore volume is in the range of from about 0.5 to about 3.5 cc/g and the average particle diameter is in the range of from about 15 to about 150 xcexcm. Most desirably the surface area is in the range of from about 100 to about 400 m2/g, the pore volume is in the range of from about 0.8 to about 3.0 cc/g and the average particle diameter is in the range of from about 20 to about 100 xcexcm. The average pore diameter of typical porous silicon dioxide support materials is in the range of from about 10 to about 1000 xc3x85. Desirably, the support material has an average pore diameter of from about 50 to about 500 xc3x85, and most desirably from about 75 to about 350 xc3x85.
Fluorine Compounds
The fluorine compounds suitable for providing fluorine for the support are desirably inorganic fluorine containing compounds. Such inorganic fluorine containing compounds may be any compound containing a fluorine atom as long as it does not contain a carbon atom. Particularly desirable are inorganic fluorine containing compounds selected from the group consisting of NH4BF4, (NH4)2SiF6, NH4PF6, NH4F, (NH4)2TaF7, NH4NbF4, (NH4)2GeF6, (NH4)2SmF6, (NH4)2TiF6, (NH4)2ZrF6, MoF6, ReF6, GaF3, SO2ClF, F2, SiF4, SF6, ClF3, ClF5, BrF5, IF7, NF3, HF, BF3, NHF2 and NH4HF2. Of these, ammonium hexafluorosilicate and ammonium tetrafluoroborate are more desirable.
Ammonium hexafluorosilicate and ammonium tetrafluoroborate fluorine compounds are typically solid particulates as are the silicon dioxide supports. A desirable method of treating the support with the fluorine compound is to dry mix the two components by simply blending at a concentration of from 0.01 to 10.0 millimole F/g of support, desirably in the range of from 0.05 to 6.0 millimole F/g of support, and most desirably in the range of from 0.1 to 3.0 millimole F/g of support. The fluorine compound can be dry mixed with the support either before or after charging to the vessel for dehydration or calcining the support. Accordingly, the fluorine concentration present on the support is in the range of from 0.6 to 3.5 wt % of support.
Another method of treating the support with the fluorine compound is to dissolve the fluorine in a solvent, such as water, and then contact the support with the fluorine containing solution. When water is used and silica is the support, it is desirable to use a quantity of water which is less than the total pore volume of the support.
Dehydration or calcining of the silica is not necessary prior to reaction with the fluorine compound. Desirably the reaction between the silica and fluorine compound is carried out at a temperature of from about 100xc2x0 C. to about 1000xc2x0 C., and more desirably from about 200xc2x0 C. to about 600xc2x0 C. for about two to eight hours.
In one embodiment, the resulting support composition may be generically represented by the formula:
Sup F
xe2x80x9cSupxe2x80x9d is a support, xe2x80x9cFxe2x80x9d is a fluorine atom bound to the support. The fluorine atom may be bound, directly or indirectly, chemically or physically to the support. An example of chemical or physical bonding would be covalent and ionic bonding, respectively. The support composition desirably may be a fluorided support composition.
In another embodiment, the resulting support composition, such as a fluorided support composition, may be generically represented by the formula:
Sup L Fn.
xe2x80x9cSupxe2x80x9d is a support selected from the group which includes talc, clay, silica, alumina, magnesia, zirconia, iron oxides, boria, calcium oxide, zinc oxide, barium oxide, thoria, aluminum phosphate gel, polyvinylchloride and substituted polystyrene.
xe2x80x9cLxe2x80x9d is a first member selected from the group which includes (i) bonding, sufficient to bound the F to the Sup; (ii) B, Ta, Nb, Ge, Ga, Sn, Si, P, Ti, Mo, Re, or Zr bound to the Sup and to the F; and (iii) O bound to the Sup and bound to a second member selected from the group consisting of B, Ta, Nb, Ge, Ga, Sn, Si, P, Ti, Mo, Re, or Zr which is bound to the F;
xe2x80x9cFxe2x80x9d is a fluorine atom; and
xe2x80x9cnxe2x80x9d is a number from 1-7.
An example of such bonding sufficient to bound the F to the Sup would be chemical or physical bonding, such as, for example, covalent and ionic bonding. The support composition desirably may be a fluorided support composition.
Metallocenes
As used herein the term xe2x80x9cmetallocenexe2x80x9d means one or more compounds represented by the formula CpmMRnXq wherein Cp is a cyclopentadienyl ring which may be substituted, or derivative thereof which may be substituted, M is a Group 4, 5, or 6 transition metal, for example titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum and tungsten, R is a hydrocarbyl group or hydrocarboxy group having from one to 20 carbon atoms, X may be a halide, a hydride, an alkyl group, an alkenyl group or an arylalkyl group, and m=1-3, n=0-3, q=0-3, and the sum of m+n+q is equal to the oxidation state of the transition metal.
Methods for making and using metallocenes are very well known in the art. For example, metallocenes are detailed in U.S. Pat. Nos. 4,530,914; 4,542,199; 4,769,910; 4,808,561; 4,871,705; 4,933,403; 4,937,299; 5,017,714; 5,026,798; 5,057,475; 5,120,867; 5,132,381; 5,155,180, 5,198,401, 5,278,119; 5,304,614; 5,324,800; 5,350,723; 5,391,790; 5,436,305 and 5,510,502 each fully incorporated herein by reference.
Desirably, the metallocenes are one or more of those consistent with the formula: 
wherein M is a metal of Group 4, 5, or 6 of the Periodic Table desirably, zirconium, hafnium and titanium, most desirably zirconium;
R1 and R2 are identical or different, desirably identical, and are one of a hydrogen atom, a C1-C10 alkyl group, desirably a C1-C3 alkyl group, a C1-C10 alkoxy group, desirably a C1-C3 alkoxy group, a C6-C10 aryl group, desirably a C6-C8 aryl group, a C6-C10 aryloxy group, desirably a C6-C8 aryloxy group, a C2-C10 alkenyl group, desirably a C2-C4 alkenyl group, a C7-C40 arylalkyl group, desirably a C7-C10 arylalkyl group, a C7-C40 alkylaryl group, desirably a C7-C12 alkylaryl group, a C8-C40 arylalkenyl group, desirably a C8-C12 arylalkenyl group, or a halogen atom, desirably chlorine;
R5 and R6 are identical or different, desirably identical, are one of a halogen atom, desirably a fluorine, chlorine or bromine atom, a C1-C10 alkyl group, desirably a C1-C4 alkyl group, which may be halogenated, a C6-C10 aryl group, which may be halogenated, desirably a C6-C8 aryl group, a C2-C10 alkenyl group, desirably a C2-C4 alkenyl group, a C7-C40-arylalkyl group, desirably a C7-C10 arylalkyl group, a C7-C40 alkylaryl group, desirably a C7-C12 alkylaryl group, a C8-C40 arylalkenyl group, desirably a C8-C12 arylalkenyl group, a xe2x80x94NR215, xe2x80x94SR15, xe2x80x94OR15, xe2x80x94OSiR315 or xe2x80x94PR215 radical, wherein R15 is one of a halogen atom, desirably a chlorine atom, a C1-C10 alkyl group, desirably a C1-C3 alkyl group, or a C6-C10 aryl group, desirably a C6-C9 aryl group;
R7 is 
wherein:
R11, R12 and R13 are identical or different and are a hydrogen atom, a halogen atom, a C1-C20 alkyl group, desirably a C1-C10 alkyl group, a C1-C20 fluoroalkyl group, desirably a C1-C10 fluoroalkyl group, a C6-C30 aryl group, desirably a C6-C20 aryl group, a C6-C30 fluoroaryl group, desirably a C6-C20 fluoroaryl group, a C1-C20 alkoxy group, desirably a C1-C10 alkoxy group, a C2-C20 alkenyl group, desirably a C2-C10 alkenyl group, a C7-C40 arylalkyl group, desirably a C7-C20 arylalkyl group, a C8-C40 arylalkenyl group, desirably a C8-C22 arylalkenyl group, a C7-C40 alkylaryl group, desirably a C7-C20 alkylaryl group or R11 and R12, or R11 and R13, together with the atoms binding them, can form ring systems;
M2 is silicon, germanium or tin, desirably silicon or germanium, most desirably silicon;
R8 and R9 are identical or different and have the meanings stated for R11;
m and n are identical or different and are zero, 1 or 2, desirably zero or 1, m plus n being zero, 1 or 2, desirably zero or 1; and
the radicals R3, R4, and R10 are identical or different and have the meanings stated for R11, R12 and R13. Two adjacent R10 radicals can be joined together to form a ring system, desirably a ring system containing from about 4-6 carbon atoms.
Alkyl refers to straight or branched chain substituents. Halogen (halogenated) refers to fluorine, chlorine, bromine or iodine atoms, desirably fluorine or chlorine.
Particularly desirable transition metal compounds are compounds of the structures (A) and (B): 
wherein:
M1 is Zr or Hf, R1 and R2 are methyl or chlorine, and R5, R6 R8, R9, R10, R11 and R12 have the above-mentioned meanings.
Illustrative but non-limiting examples of desirable transition metal compounds include:
Dimethylsilandiylbis (2-methyl-4-phenyl-1-indenyl)Zirconium dimethyl
Dimethylsilandiylbis(2-methyl-4,5-benzoindenyl) Zirconium dimethyl;
Dimethylsilandiylbis(2-methyl-4,6-diisopropylindenyl) Zirconium dimethyl;
Dimethylsilandiylbis(2-ethyl-4-phenyl-1-indenyl) Zirconium dimethyl;
Dimethylsilandiylbis(2-ethyl-4-naphthyl-1-indenyl Zirconium dimethyl,
Phenyl(methyl)silandiylbis(2-methyl-4-phenyl)-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-4-(1-naphthyl)-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-4-(2-naphthyl)-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-4,5-disopropyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2,4,6-trimethyl-1-indenyl Zirconium dimethyl,
Phenyl(methyl)silandiylbis(2-methyl-4,6-diisopropyl-1-indenyl)Zirconium dimethyl,
1,2-Ethandiylbis(2-methyl-4,6-diisopropyl-1-indenyl Zirconium dimethyl,
1,2-Butandiylbis(2-methyl-4,6-diisopropyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-4-ethyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-4-isopropyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-4-t-butyl-1-indenyl Zirconium dimethyl,
Phenyl(methyl)silandiylbis(2-methyl-4-isopropyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-ethyl-4-methyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2,4-dimethyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-4-ethyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-xcex1-acenaphth-1-indenyl Zirconium dimethyl,
Phenyl(methyl)silandiylbis(2-methyl-4,5-benzo-1-indenyl Zirconium dimethyl,
Phenyl(methyl)silandiylbis(2-methyl-4,5-(methylbenzo)-1-indenyl)Zirconium dimethyl,
Phenyl(methyl)silandiylbis(2-methyl-4,5-(tetramethylbenzo)-1-indenyl)Zirconium dimethyl,
Phenyl(methyl)silandiylbis(2-methyl-a-acenaphth-1-indenyl)Zirconium dimethyl,
1,2-Ethandiylbis(2-methyl-4,5-benzo-1-indenyl Zirconium dimethyl,
1,2-Butandiylbis(2-methyl-4,5-benzo-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-4,5-benzo-1-indenyl Zirconium dimethyl,
1,2-Ethandiylbis(2,4,7-trimethyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-1-indenyl Zirconium dimethyl,
1,2-Ethandiylbis(2-methyl-1-indenyl Zirconium dimethyl,
Phenyl(methyl)silandiylbis(2-methyl-1-indenyl Zirconium dimethyl,
Diphenylsilandiylbis(2-methyl-1-indenyl Zirconium dimethyl,
1,2-Butandiylbis(2-methyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-ethyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-5-isobutyl-1-indenyl Zirconium dimethyl,
Phenyl(methyl)silandiylbis(2-methyl-5-isobutyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-5-t-butyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2,5,6-trimethyl-1-indenyl Zirconium dimethyl,
Dimethylsilandiylbis(2-methyl-4-phenyl-1-indenyl)Zirconium dichloride
Dimethylsilandiylbis(2-methyl-4,5-benzoindenyl) Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-4,6-diisopropylindenyl)Zirconium dichloride,
Dimethylsilandiylbis(2-ethyl-4-phenyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis (2-ethyl-4-naphthyl-1-indenyl Zirconium dichloride,
Phenyl(methyl)silandiylbis(2-methyl-4-phenyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-4-(1-naphthyl)-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-4-(2-naphthyl)-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-4,5-diisopropyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2,4,6-trimethyl-1-indenyl Zirconium dichloride,
Phenyl(methyl)silandiylbis(2-methyl-4,6-diisopropyl-1-indenyl Zirconium dichloride,
1,2-Ethandiylbis(2-methyl-4,6-diisopropyl-1-indenyl Zirconium dichloride,
1,2-Butandiylbis(2-methyl-4,6-diisopropyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-4-ethyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-4-isopropyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-4-t-butyl-1-indenyl Zirconium dichloride,
Phenyl(methyl)silandiylbis(2-methyl-4-isopropyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-ethyl-4-methyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2,4-dimethyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-4-ethyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-xcex1-acenaphth-1-indenyl Zirconium dichloride,
Phenyl(methyl)silandiylbis(2-methyl-4,5-benzo-1-indenyl Zirconium dichloride,
Phenyl(methyl)silandiylbis(2-methyl-4,5-(methylbenzo)-1-indenyl)Zirconium dichloride,
Phenyl(methyl)silandiylbis(2-methyl-4,5-(tetramethylbenzo)-1-indenyl Zirconium dichloride,
Phenyl(methyl)silandiylbis (2-methyl-a-acenaphth-1-indenyl Zirconium dichloride,
1,2-Ethandiylbis(2-methyl-4,5-benzo-1-indenyl Zirconium dichloride,
1,2-Butandiylbis(2-methyl-4,5-benzo-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-4,5-benzo-1-indenyl Zirconium dichloride,
1,2-Ethandiylbis(2,4,7-trimethyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-1-indenyl Zirconium dichloride,
1,2-Ethandiylbis(2-methyl-1-indenyl Zirconium dichloride,
Phenyl(methyl)silandiylbis(2-methyl-1-indenyl Zirconium dichloride,
Diphenylsilandiylbis(2-methyl-1-indenyl Zirconium dichloride,
1,2-Butandiylbis(2-methyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-ethyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-5-isobutyl-1-indenyl Zirconium dichloride,
Phenyl(methyl)silandiylbis(2-methyl-5-isobutyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2-methyl-5-t-butyl-1-indenyl Zirconium dichloride,
Dimethylsilandiylbis(2,5,6-trimethyl-1-indenyl Zirconium dichloride, and the like.
Many of these desirable transition metal compound components are described in detail in U.S. Pat. Nos. 5,145,819; 5,243,001; 5,239,022; 5,329,033; 5,296,434; 5,276,208; 5,672,668, 5,304,614 and 5,374,752; and EP 549 900 and 576 970 all of which are herein fully incorporated by reference.
Additionally, metallocenes such as those described in U.S. Pat. No. 5,510,502, U.S. Pat. No. 4,931,417, U.S. Pat. No. 5,532,396, U.S. Pat. No. 5,543,373, WO 98/014585, EP611 773 and WO 98/22486 (each fully incorporated herein by reference) are suitable for use in this invention.
Activators
Metallocenes are generally used in combination with some form of activator in order to create an active catalyst system. The term xe2x80x9cactivatorxe2x80x9d is defined herein to be any compound or component, or combination of compounds or components, capable of enhancing the ability of one or more metallocenes to polymerize olefins to polyolefins. Alklyalumoxanes such as methylalumoxane (MAO) are commonly used as metallocene activators. Generally alkylalumoxanes contain about 5 to 40 of the repeating units: 
AIR2 for linear species and for cyclic species
where R is a C1-C8 alkyl including mixed alkyls. Particularly desirable are the compounds in which R is methyl. Alumoxane solutions, particularly methylalumoxane solutions, may be obtained from commercial vendors as solutions having various concentrations. There are a variety of methods for preparing alumoxane, non-limiting examples of which are described in U.S. Pat. Nos. 4,665,208, 4,952,540, 5,091,352, 5,206,199, 5,204,419, 4,874,734, 4,924,018, 4,908,463, 4,968,827, 5,308,815, 5,329,032, 5,248,801, 5,235,081, 5,103,031 and EP-A-0 561 476, EP-B1-0 279 586, EP-A-0 594-218 and WO 94/10180, each fully incorporated herein by reference. (as used herein unless otherwise stated xe2x80x9csolutionxe2x80x9d refers to any mixture including suspensions.)
Ionizing activators may also be used to activate metallocenes. These activators are neutral or ionic, or are compounds such as tri(n-butyl)ammonium tetrakis(pentaflurophenyl)borate, which ionize the neutral metallocene compound. Such ionizing compounds may contain an active proton, or some other cation associated with, but not coordinated or only loosely coordinated to, the remaining ion of the ionizing compound. Combinations of activators may also be used, for example, alumoxane and ionizing activators in combinations, see for example, WO 94/07928.
Descriptions of ionic catalysts for coordination polymerization comprised of metallocene cations activated by non-coordinating anions appear in the early work in EP-A-0 277 003, EP-A-0 277 004 and U.S. Pat. No. 5,198,401 and WO-A-92/00333 (incorporated herein by reference). These teach a desirable method of preparation wherein metallocenes (bisCp and monoCp) are protonated by an anion precursor such that an alkyl/hydride group is abstracted from a transition metal to make it both cationic and charge-balanced by the non-coordinating anion. Suitable ionic salts include tetrakis-substituted borate or aluminum salts having fluorided aryl-constituents such as phenyl, biphenyl and napthyl.
The term xe2x80x9cnoncoordinating anionxe2x80x9d (NCA) means an anion which either does not coordinate to said cation or which is only weakly coordinated to said cation thereby remaining sufficiently labile to be displaced by a neutral Lewis base. xe2x80x9cCompatiblexe2x80x9d noncoordinating anions are those which are not degraded to neutrality when the initially formed complex decomposes. Further, the anion will not transfer an anionic substituent or fragment to the cation so as to cause it to form a neutral four coordinate metallocene compound and a neutral by-product from the anion. Noncoordinating anions useful in accordance with this invention are those which are compatible, stabilize the metallocene cation in the sense of balancing its ionic charge in a +1 state, yet retain sufficient lability to permit displacement by an ethylenically or acetylenically unsaturated monomer during polymerization.
The use of ionizing ionic compounds not containing an active proton but capable of producing both the active metallocene cation and a noncoordinating anion is also known. See, for example, EP-A-0 426 637 and EP-A-0 573 403 (incorporated herein by reference). An additional method of making the ionic catalysts uses ionizing anion precursors which are initially neutral Lewis acids but form the cation and anion upon ionizing reaction with the metallocene compounds, for example the use of tris(pentafluorophenyl) borane. See EP-A-0 520 732 (incorporated herein by reference). Ionic catalysts for addition polymerization can also be prepared by oxidation of the metal centers of transition metal compounds by anion precursors containing metallic oxidizing groups along with the anion groups, see EP-A-0 495 375 (incorporated herein by reference).
Where the metal ligands include halogen moieties (for example, bis cyclopentadienyl zirconium dichloride) which are not capable of ionizing abstraction under standard conditions, they can be converted via known alkylation reactions with organometallic compounds such as lithium or aluminum hydrides or alkyls, alkylalumoxanes, Grignard reagents, etc. See EP-A-0 500 944 and EP-A1-0 570 982 (incorporated herein by reference) for in situ processes describing the reaction of alkyl aluminum compounds with dihalo-substituted metallocene compounds prior to or with the addition of activating anionic compounds.
Desirable methods for supporting ionic catalysts comprising metallocene cations and NCA are described in U.S. Pat. No. 5,643,847, U.S. patent application Ser. No. 09184358, filed Nov. 2, 1998 and U.S. patent application Ser. No. 09/184389, filed Nov. 2, 1998 (all fully incorporated herein by reference). When using the support composition, and particularly the fluorided support composition, of this invention, these NCA support methods generally comprise using neutral anion precursors that are sufficiently strong Lewis acids to react with the hydroxyl reactive functionalities present on the silica surface such that the Lewis acid becomes covalently bound.
In one embodiment of this invention, the activator is one or more NCAs and the supportation method described above is used. This reaction can be generically represented by the chemical formula:
[LnLxe2x80x2mMxe2x80x2Rxe2x80x2]+[LA-O-SupLFn]xe2x88x92,xe2x80x83xe2x80x83(1)
where [LnLxe2x80x2mMxe2x80x2Rxe2x80x2]+ is the catalytically active transition metal cation and LA-Oxe2x80x94 is the activator anion bound to the support composition, particularly the fluorided support composition, SupLFn. More specifically, Ln is one or more ligands (n equals d0xe2x88x921 where d0 is the highest oxidation state of Mxe2x80x2) covalently bound to Mxe2x80x2, Lxe2x80x2m is a neutral, non-oxidizing ligand having a dative bond to Mxe2x80x2 (typically m equals 0 to 3), Mxe2x80x2 is a Group 4, 5, 6, 9, or 10 transition metal, Rxe2x80x2 is a ligand having a "sgr" bond to Mxe2x80x2 into which a polymerizable monomer or macromonomer can insert for coordination polymerization. LA is a Lewis acid that is capable of forming the anionic activator and O is oxygen.
The activator anion neutral precursors that serve as the Lewis acid (LA) include any of the noncoordinating anion precursors of sufficient acidity to accept the available electron pair of the hydroxyl group oxygen atom and facilitate the protonation of the transition metal compound or a secondary proton acceptor (see below) by the silanol group proton. The desirable activator anion neutral precursors that serve as the Lewis acid (LA) are strong Lewis acids with non-hydrolyzable ligands, at least one of which is electron-withdrawing, such as those Lewis acids known to abstract an anionic fragment from dimethyl zirconocene (biscyclopentadienyl zirconium dimethyl) e.g., tris-perfluorophenyl borane, trisperfluoronaphthyl borane, trisperfluorobiphenyl borane. These precursors therefore should not possess any reactive ligands, which can be protonated by any remaining hydroxyl groups on the support composition, particularly the fluorided support composition. For example, any Group 13 element based Lewis acids having only alkyl, halo, alkoxy, and/or amido ligands, which are readily hydrolyzed in aqueous media, may not be suitable. At least one ligand of LA must be sufficiently electron-withdrawing to achieve the needed acidity, for example, tris-perfluorophenyl borane, under typical reaction conditions. Typical metal/metalloid centers for LA will include boron, aluminum, antimony, arsenic, phosphorous and gallium. Most desirably LA is a neutral compound comprising a Group 13 metalloid center with a complement of ligands together sufficiently electron-withdrawing such that the Lewis acidity is greater than or equal to that of AlCl3. Examples include tris-perfluorophenylborane, tris(3,5-di(trifluoromethyl)phenyl)borane, tris(di-t-butylmethylsilyl)perfluorophenylborane, and other highly fluorinated tris-arylborane compounds.
Additionally, when the activator for the metallocene supported catalyst composition is a NCA, desirably the NCA is first added to the support composition followed by the addition of the metallocene catalyst. When the activator is MAO, desirably the MAO and metallocene catalyst are dissolved together in solution. The support is then contacted with the MAO/metallocene catalyst solution. Other methods and order of addition will be apparent to those skilled in the art.
Polymerization
The metallocene supported catalyst composition is useful in coordination polymerization of unsaturated monomers conventionally known to be polymerizable under coordination polymerization conditions. Such conditions also are well known and include solution polymerization, slurry polymerization, and low pressure gas phase polymerization. The metallocene supported catalysts compositions of the present invention are thus particularly useful in the known operating modes employing fixed-bed, moving-bed, fluid-bed, or slurry processes conducted in single, series or parallel reactors.
The metallocene supported catalyst composition of this invention are particularly suitable for propylene polymerizations. Any process may be used, but propylene polymerizations are most commonly conducted using a slurry processes in which the polymerization medium can be either a liquid monomer, like propylene, or a hydrocarbon solvent or diluent, advantageously aliphatic paraffin such as propane, isobutane, hexane, heptane, cyclohexane, etc. or an aromatic diluent such as toluene. The polymerization temperatures may be those considered low, e.g., less than 50xc2x0 C., desirably 0xc2x0 C.-30xc2x0 C., or may be in a higher range, such as up to about 150xc2x0 C., desirably from 50xc2x0 C. up to about 80xc2x0 C., or at any ranges between the end points indicated. Pressures can vary from about 100 to about 700 psia (0.69-4.8 MPa). Additional description is given in U.S. Pat. Nos. 5,274,056 and 4,182,810 and WO 94/21962 which are each fully incorporated by reference.
Propylene homopolymers may be formed with the metallocene supported catalyst composition using conventional polymerization techniques. The microstructure of the homopolymer will desirably possess a meso run length as measured by 13C NMR of 70% or greater relative to the total polymer produced. Copolymers with ethylene may be formed by introduction of ethylene to the propylene slurry or gas phase polymerization of gaseous propylene and ethylene comonomers. Copolymers with ethylene desirably contain 0.1 to 10 wt % comonomer. Stereoregular homopolymers and copolymers of xcex1-olefins may be formed with this system by introduction of the appropriate monomer or monomers to a slurry or bulk propylene process.
Pre-polymerization may also be used for further control of polymer particle morphology in typical slurry or gas phase reaction processes in accordance with conventional teachings. For example such can be accomplished by pre-polymerizing a C2-C6 alpha-olefin for a limited time, for example, ethylene is contacted with the supported metallocene catalyst composition at a temperature of xe2x88x9215 to 30xc2x0 C. and ethylene pressure of up to about 250 psig (1724 kPa) for 75 min. to obtain a polymeric coating on the support of polyethylene of 30,000-150,000 molecular weight. The pre-polymerized catalyst is then available for use in the polymerization processes referred to above. In a similar manner, the activated catalyst on a support coated with a previously polymerized thermoplastic polymer can be utilized in these polymerization processes.
Additionally it is desirable to reduce or eliminate polymerization poisons that may be introduced via feedstreams, solvents or diluents, by removing or neutralizing the poisons. For example, monomer feed streams or the reaction diluent may be pre-treated, or treated in situ during the polymerization reaction, with a suitable scavenging agent. Typically such will be an organometallic compound employed in processes such as those using the Group-13 organometallic compounds of U.S. Pat. No. 5,153,157 and WO-A-91/09882 and WO-A-94/03506, noted above, and that of WO-A-93/14132.